Bicycle with rear drive assembly for elliptical movement

ABSTRACT

A bicycle with a rear drive assembly configured to allow pedal boards to be pivotable while moving in an elliptical trajectory and which allows a cyclist to ride in an erect position is disclosed. A front end of each of the pedal boards is pivotably connected to an end of a crank and each of the pedal boards is connected to or integral with a guide rod extending rearwardly from the pedal board. The guide rods are supported by a rear drive assembly comprising a transverse tube that is horizontally connected to a frame of the bicycle. A roller is mounted at each end of the transverse tube. Each roller has a groove which accommodates the cross-section of the guide rod.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a 371 of PCT/BR2013/000473, filed Nov. 7, 2013,which claims priority from Brazilian Patent Application. No. BR 10 2012028693 9, filed Nov. 9, 2012, which is hereby incorporated herein byreference in its entirety.

FIELD

Embodiments disclosed herein relate generally to the field of bicycles,and, more specifically, to bicycles having a rear drive assembly thatenables cyclists to ride in an erect position.

BACKGROUND

Conventional bicycles include a normally tubular frame with a frontwheel capable of being steered by a handlebar, as well as a rear wheelequipped with a ratchet mechanism mounted on the rear wheel's hub. Theratchet mechanism is driven by a chain that extends around a sprocketdriven by pedals mounted on cranks. This type of bicycle, according tothe most varied types of configurations, has a seat on which a cyclistcan sit. Nonetheless, the movement carried out by the user of thisbicycle is a cyclical motion and therefore not natural, like walking.

Attempts have been made to introduce a type of drive for bicycleswhereby a cyclist can ride a vehicle of this kind while in an erectposition, as in U.S. Pat. No. 8,162,338, issued Apr. 24, 2012, where therear portion of the proposed bicycle has a structure where the sprocketis mounted and connected to the ratchet mechanism via a chain. With thistype of bicycle, the sprocket is driven by cranks that, instead of beingequipped with conventional pedals, are linked to long rods whose endsinclude platforms for the cyclist's feet. One platform is provided forthe right foot and another platform is provided for the left foot. Eachplatform has its own rod for connection to the crank.

In this type of bicycle, the front end of each platform for a cyclist'sfeet contains a pulley that moves on a tubular track positioned in aslightly tilted manner, so that the cyclist travels forward in analternating manner on the platforms via elliptical movements that aresimilar to normal human striding. These movements are translated into anangular oscillating motion of the rods and are subsequently convertedinto the rotary motion of the sprocket to produce the correspondingmovement of rotary motion of the ratchet mechanism connected to the hubof the rear wheel.

This type of bicycle has a series of disadvantages that, for example,include the fact that substantial alteration of a bicycle's structure isnecessary in order to accommodate the sprocket/ratchet assembly locatedabove the rear wheel in the rear portion, thus creating an unusually andexcessively complex design structure with costs exceeding the normalcosts associated with ordinary bicycles.

Another conventional design includes the design for a vehicle describedby U.S. Pat. No. 7,803,090, issued Sep. 28, 2010. This vehicle is notactually a bicycle because it has three wheels, with two front wheelsand one rear wheel.

The vehicle described in U.S. Pat. No. 7,803,090 is a hybrid tricyclewith a drive system generically analogous to the one described indocument U.S. Pat. No. 8,162,338, since it uses rods connected tomountings for the feet in order to directly move the rear wheel. Thisconstitutes the drive unit for the vehicle.

The aforementioned tricycle consists of an elliptical machine thatimitates normal human striding, and its steering is even more complexand is based on a design where simplicity is not a priority. It is alsoa relatively long, wide, and heavy machine, and therefore constitutes alimited means of transportation.

Additionally, in relation to these types of vehicles belonging to thestate of the art and more specifically in terms of this last example ofa three-wheeled vehicle, also known as “Street Strider,” a sharedfeature can be observed whereby both of them produce a form of movementof the cyclist's feet that can be regarded or defined as beingessentially elliptical.

In general terms, the type of elliptical motion identified in the abovetwo vehicles, and that can be defined as elliptical, has been found tobe more efficient than the turning motion produced by more conventionalbicycles, insofar as an elliptical trajectory more closely approximatesthe natural motion that characterizes human striding.

SUMMARY

Embodiments overcome the disadvantages of the prior art. Embodimentswere developed in consideration of the previously described state of theart. Embodiments describe a bicycle's configuration partly being that ofa conventional bicycle, while replacing the pedals with wide pedalboards to accommodate the cyclist's entire foot, and the pedal boardsare mounted on respective cranks for driving a sprocket/ratchet systemin a conventional manner. The system's ratchet mechanism is likewisemounted on the hub of the bicycle's rear wheel in a conventional manner.

Each pedal board on the bicycle has a guide rod that meets with asliding mount on the rear portion of the bicycle. This mount can bebased on adoption of a rotation for each of the rods, for example.

In a different manner from that which is observed among theabove-mentioned conventional vehicles, embodiments provide a bicyclewith pedal boards which provide circular motion that is naturallycombined with angular motion controlled by the guide rods. As a result,the cyclist can ride in an erect position, while using movements thatare entirely natural.

Embodiments favorably combine elementary aspects of conventionalbicycles with a wholly innovative distinctive drive system, and a uniquetechnical result is obtained from this synergistic combination, wherebythis vehicle, in spite of its possessing a distinctive drive system,offers a mode of operation that is not unusual to cyclists.

Moreover, the bicycle is the result of a design that prioritizesstructural simplicity and complete functionality. A vehicle that iscapable of being produced on a large scale at an extremely competitivecost can, therefore, be obtained.

The type of movement obtained may be defined and regarded as essentiallyelliptical, as has been observed in relation to the state of the artexamples mentioned above, with this type of movement being obtainedbased on a design that, as stated above, gives priority to structuralsimplicity and complete functionality. In this instance, the designresults in a vehicle that can be manufactured in a more economical wayby using standard and simpler parts and using a more conventionalconstruction process that is available throughout the world. The bicycleprovides a type of movement that simulates the way a human moves, inaddition to being configured as a way to increase speed on straightawaysand as a way to increase torque when the cyclist is using the bicycle toconquer steep terrain, such as hills, mountains, etc.

Furthermore, the bicycle has the role of a vehicle with applications forleisure, transportation, and sports that can be accomplished in a moreergonomic manner than what has been encountered with regard toconventional bicycles that, not infrequently, cause cyclists toexperience discomfort that can include numbness in their hands and feet,and pain in the spine when used for longer distances, inter alia.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description will refer to the following drawings, whereinlike numerals refer to like elements, and wherein:

FIG. 1 illustrates a perspective view of a configuration of a bicyclebeing described herein;

FIG. 2 illustrates an overhead view of the bicycle configuration shownin FIG. 1;

FIG. 3A illustrates a detailed perspective view of the rear portion ofthe bicycle described herein, depicting where mountings/rollers for theguide rods are located;

FIG. 3B illustrates an enlarged detailed schematic view taken from aportion of FIG. 3A, which depicts a first variation of the assemblyformed by the mountings and the guide rods;

FIG. 3C illustrates an enlarged detailed schematic view taken from aportion of FIG. 3A, which depicts a second variation of the assemblyformed by the mountings and the guide rods;

FIG. 4 illustrates a detailed perspective view of the rear portion ofthe bicycle described herein, depicting a third variation of theassembly formed by the mountings and the guide rods;

FIG. 5 illustrates a detailed perspective view of the rear portion ofthe bicycle described herein, depicting a fourth variation of theassembly formed by the mountings and the guide rods;

FIG. 6 illustrates a detailed perspective view of the rear portion ofthe bicycle described herein, depicting a fifth variation of theassembly formed by the mountings and the guide rods; and

FIG. 7 illustrates a detailed perspective view of the rear portion ofthe bicycle described herein, depicting a sixth variation of theassembly formed by the mountings and the guide rods, where a pivotingretaining ring is provided for each rod on each of the rollers. Thisring's function is to prevent the rods from coming out of theirrespective rollers.

DETAILED DESCRIPTION

In accordance with that illustrated in the above-described drawings,FIG. 1 illustrates a bicycle 1 which has a tubular frame 2, that, in aconventional manner, includes a front handlebar 3 forcontrolling/steering a front wheel 5 via a fork 4 which is operativelyconnected between the handlebar 3 and the front wheel 5. The tubularframe 2 is outfitted with a central moving assembly 26 that includes asprocket 7. FIG. 2 illustrates an overhead view of the bicycle 1 shownin FIG. 1.

The sprocket 7 has respective cranks 8 and is surrounded by a chain 9extending toward the rear portion of the tubular frame 2, towards thelocation where the rear wheel 10 is mounted and driven by a ratchetmechanism 11 as is conventionally known.

A difference of the bicycle 1 as compared to conventional bicycles isthat the front end of each of the pedal boards 12 pivots on the ends ofthe respective cranks 8, with a guide rod 13 extending from each pedalboard 12 in the opposite direction. In other words, the front end ofeach of the pedal boards is pivotably connected to an end of the crank,and each of the pedal boards are connected to or integral with a guiderod extending rearwardly from the pedal board.

FIG. 3A illustrates a detailed perspective view of the rear portion ofthe bicycle 1, depicting where mountings (main rollers 16) for the guiderods 13 are located. The guide rods 13 are supported on the rear driveassembly (or rear sliding support assembly) 14 which comprises atransverse tube 15 horizontally integral with the frame 2. Each end ofthe transverse tube 15 accommodates a roller 16 containing a groove 16Awhich is suitably sized for accommodating the cross-section of thecorresponding guide rod 13.

The bicycle 1 is propelled by the action of the sprocket 7 via thecranks 8, and this assembly rotates around the central moving axle 6.The cranks 8 and the pedal boards 12 rotate around the same axle 6 inthe central moving assembly 26. The pedal boards 12 pivot while theyexecute angular movement determined by the positioning of the guide rods13 on the respective roller 16.

As can be easily understood, the movement that propels the bicycle 1 ismuch more natural because the pedal boards 12 rotate around the sprocket7 in a manner analogous to that which is observed in relation to pedalson conventional bicycles.

The rear drive assembly and use of the guide rods and pivotable pedalboards allow the cyclist to operate the bicycle in an erect positionwithout requiring elimination of the conventional power transmissionsystem that begins with the cranks 8, passing through the sprocket 7 andthe chain 9, and ending at the ratchet mechanism 11 and the rear wheel10.

A first variation of bicycle 1 is illustrated in FIG. 3B. This variationdiffers from the principal configuration of FIGS. 1-3A insofar as therear drive assembly 14, in general, where there are rollers 16 with agroove 16A configured to accommodate a guide rod 13A having a V-shapedprofile.

FIG. 3C illustrates a second variation of a rear drive assembly 14 ofbicycle 1, where a roller 16 is provided having a groove 16A configuredto accommodate a guide rod 13B having a triangular tubular profile.

FIG. 4 illustrates a third variation of a rear drive assembly 14 ofbicycle 1. In rear drive assembly 14, rollers 16 with grooves 16A thatare proportionally deeper are provided, and this fact increases theactual retention capability for the guide rods 13 to be supported withinthe grooves 16A of the rollers 16.

A fourth variation of bicycle 1 is illustrated in FIG. 5, where reardrive assembly 14 includes a structure 17 in the shape of an inverted“U” around each roller 16. In its upper portion, this U-shaped structure17 has an auxiliary roller 18 that may have a smaller diameter than thediameter chosen for the rollers 16.

The U-shaped structure 17 is mounted in such a manner as to rotatearound the same shaft 20 as its respective roller 16, thereby allowingthe auxiliary roller 18 to be capable of assuming a position ofopposition to the movement of the guide rod 13 when moving away from theroller 16 at any angle that may be assumed by the guide rod 13 duringits movement.

FIG. 6 illustrates a fifth variation of a rear drive assembly 14 ofbicycle 1, where rear drive assembly 14 involves the use of a pair ofrollers 16 (i.e., the primary roller and a secondary roller) that aremounted on a pivoting structure 19 (of which only one is visible) thatrotates around respective shafts 20, with the rollers 16 of this fifthvariation being of the same type as the rollers 16 provided in theprincipal configuration of rear drive assembly 14 illustrated in FIGS.1-3A described above.

In any of the above-mentioned variations of the rear drive assembly 14of bicycle 1 illustrated in FIGS. 1-6, each of the guide rods 13, 13A,13B is positioned so as to maintain permanent contact with the rollers16 of rear drive assembly 14 during the entire cycle of movement of thepedal boards 12.

Following the same principle above, a sixth variation of a rear driveassembly 14 of bicycle 1 is illustrated in FIG. 7. In this variation,the rear drive assembly 14 includes a retaining ring X which pivotsabout each of the respective rollers 16. Retaining ring X also has thefunction of preventing the guide rods 13 from coming out of theirrespective grooves 16A.

The bicycle, 1, being described herein presents a substantially simplerand more functional configuration when compared to the conventionalvehicles mentioned above representing the state of the art.

Those of ordinary skill in the art will recognize that variousmodifications and variations may be made to the embodiments describedabove without departing from the spirit and scope of the presentinvention. It is therefore to be understood that the present inventionis not limited to the particular embodiments disclosed above, but it isintended to cover such modifications and variations as defined by thefollowing claims.

What is claimed is:
 1. A bicycle with a rear drive assembly configuredto allow pedal boards to be pivotable while moving in an ellipticaltrajectory, the bicycle comprising: a front wheel; a rear wheel having aratchet mounted thereon for driving the rear wheel; a tubular frameincluding a front handlebar that controls the front wheel via a forkwhich is operatively connected between the handlebar and the frontwheel; a central drive assembly including a sprocket and cranksextending from the sprocket; a chain surrounding the sprocket andextending toward a rear portion of the tubular frame in order to drivethe ratchet; pedal boards having front and rear ends, wherein the frontend of each of the pedal boards is pivotably connected to an end of thecrank; a guide rod extending rearwardly from each of the pedal boards; arear drive assembly comprising: a transverse tube connected to thetubular frame in a vicinity of the rear wheel; and a primary rollermounted at each end of the transverse tube, each primary roller having agroove along a perimeter of the primary roller that accommodates across-section of the guide rod; wherein the pedal boards are pivotablewhile moving in an elliptical trajectory.
 2. The bicycle of claim 1wherein each of the guide rods has a V-shaped cross-sectional profileextending longitudinally along the guide rod, wherein the groove of eachprimary roller is configured to accommodate the guide rod having theV-shaped cross-sectional profile.
 3. The bicycle of claim 1 wherein eachof the guide rods has a tubular triangular cross-sectional profileextending longitudinally along the guide rod, wherein the groove of eachprimary roller is configured to accommodate the guide rod having thetubular triangular cross-sectional profile.
 4. The bicycle of claim 1wherein a depth of the groove of each primary roller is suitably largeso as to completely contain the cross-section of the guide rod when thecross-section of the guide rod is accommodated by the groove.
 5. Thebicycle of claim 1 wherein the rear drive assembly further comprises aU-shaped structure positioned around each of the primary rollers, anupper portion of the U-shaped structure contains an auxiliary roller,whereby the auxiliary roller and the primary roller accommodate andallow sliding of the guiding rod therebetween.
 6. The bicycle of claim 5wherein the U-shaped structure and the primary roller are mounted sothat they are rotatable around a common shaft.
 7. The bicycle of claim 1wherein the rear drive assembly further comprises a secondary rollerpositioned opposite each of the primary rollers, whereby the secondaryroller and the primary roller accommodate and allow sliding of theguiding rod therebetween.
 8. The bicycle of claim 7 wherein thesecondary roller and the primary roller are mounted in a pivotingstructure that is rotatable around a common shaft.
 9. The bicycle ofclaim 1 wherein the rear drive assembly further comprises a retainingring pivotably mounted around each of the primary rollers, wherein theretaining ring and the primary roller are positioned to accommodate andallow sliding of the guiding rod therebetween, and wherein the retainingring maintains the guide rod within the groove by preventing separationof the guide rod from the groove.
 10. The bicycle of claim 1 wherein theguide rod extends from the rear end of each of the pedal boards.